The present invention relates to a process for the preparation of acetoxybutanols by hydrogenation of acetoxybutyraldehydes.
The acetoxybutanols are valuable starting materials for the preparation of butanediols. Butanediols are industrially used solvents and intermediate products for the preparation of polyurethanes, epoxide resins, polyesters, polyamides and plasticisers. 1,4-butanediol is particularly suitable for the preparation of polyurethanes and thermoplasts (Kirk-Othmer, Encyclopedia of Chemical Technology, 2nd Ed., Vol 10, 672 (1966)). 1,2-Butanediol can be processed to alkyd resins (U.S. Pat. No. 2.965.587); 2-methyl-1,3-propanediol is a valuable starting material for the production of polyesters from which dyeable fibres can be manufactured (French Specification No. 1.303.888).
It is known to convert 2-acetoxybutyraldehyde to the corresponding butanediol by hydrogenation and hydrolysis (U.S. Pat. No. 2,428,760, column 2, lines 50 to 55).
Catalysts based on metals of group VIII of the periodic table are suitable for the preparation of acetoxybutanol from acetoxybutyraldehyde by hydrogenation with hydrogen. For example, the hydrogenation can be carried out with nickel, cobalt or noble metal catalysts, such as palladium. For industrial use of the process it is of interest to achieve a high speed of hydrogenation and practically quantitative conversion of the aldehyde to the alcohol.